Although FL has promoted collaborative learning while preserving user privacy, it still faces a challenge of incentivizing clients to participate in the FL process blackand contribute their data as well as computation resources. blackWithout a proper incentive mechanism, clients may not be willing to join the data training which would reduce the scalability of the designed FL system [1]}. Recently, blockchain has emerged as an attractive tool to blackfacilitate transparent economic mechanism designs, so as to boost the FL training in FLchain systems.
